anxiety disorder: Differential diagnosis and cognitive behavioral treatment Generalized
Michel J. Dugas, Ph.D.
This paper summarizes the workshop I had the pleasure of presenting at CPA 2000 in Ottawa. The workshop was divided into five sections:
(1) Introduction and clinical presentation,
(2) Differential diagnosis,
(3) Cognitive processes,
(4) Assessment, and
(5) Cognitive-behavioral treatment. Each of these sections is briefly described below.
Introduction and clinical presentation
The main feature of generalized anxiety disorder (GAD) is excessive and uncontrollable worry and anxiety occurring more days than not for at least six months. Furthermore, the worry and anxiety are associated with at least three of the following six somatic symptoms: restlessness, being easily fatigued, difficulty concentrating, irritability, muscle tension, and sleep disturbance. Because the somatic symptoms are also found in other anxiety and mood disorders, clinicians should focus on worry when investigating the presence of GAD.
Differential diagnosis
Given that the DSM-IV is somewhat unclear about diagnostic boundaries between GAD and other disorders such as obsessive-compulsive disorder (OCD) and social phobia, the differential diagnosis of GAD can at times be quite challenging. For the 15 to 20 % of OCD clients who do not have overt compulsions, the GAD-OCD differential diagnosis rests on the form and function of the intrusive thought. For example, worries are often egosyntonic and made up of verbal-linguistic thought, whereas obsessions tend to be egodystonic and to involve mental images. The GAD-social phobia differential diagnosis can be facilitated by remembering that GAD clients typically have many worry themes and that avoidance is often a secondary feature of the clinical picture, whereas the concerns of social phobics are oftentimes restricted to social issues and avoidance is frequently a central feature of the clinical picture.
Cognitive processes
Research suggests that a number of cognitive processes are involved in the etiology and maintenance of GAD. Our research group has identified four process variables that appear to be involved in GAD and thus represent important treatment targets: intolerance of uncertainty, cognitive avoidance, ineffective problem solving, and positive beliefs about worry. Of these four cognitive processes, intolerance of uncertainty appears to be the central process involved in high levels of worry and GAD. From a clinical perspective, we have found that GAD clients are highly intolerant of uncertainty. For example, GAD clients have told us things such as "I know there is only one chance in a million that my plane will crash, but I can't help worrying about it because it might just happen". In our clinical work, we have often used the metaphor of an "allergy" to uncertainty (where a very small quantity of a "substance" leads to a violent reaction) to help GAD clients conceptualize their relationship with uncertainty.
Assessment
Although many measures can be useful for the assessment of GAD and its consequences, we recommend that three measures be used with this clientele: the Penn State Worry Questionnaire, the Worry and Anxiety Questionnaire, and the Intolerance of Uncertainty Scale. The Penn State Worry Questionnaire contains 16 items that measure the tendency to engage in worry, regardless of worry content. The Worry and Anxiety Questionnaire includes 11 items that measure DSM-IV diagnostic criteria for GAD. Finally, the Intolerance of Uncertainty Scale contains 27 items relating to the idea that uncertainty is unacceptable, reflects badly on a person, and leads to frustration, stress, and the inability to act. All three of these self-report questionnaires can be completed as homework assignments at different times during therapy.
Cognitive-behavioral treatment
The cognitive-behavioral treatment that we have developed helps GAD clients to increase their tolerance of uncertainty by cognitively exposing themselves to their core fears, applying sound problem-solving principles to current problems, and reevaluating their beliefs about the usefulness of worrying. For example, clients learn to address the uncertainty of the problem-solving process "head on" by applying promising solutions rather than waiting for the perfect solution. So far, data from our clinical trials has been quite encouraging. In a recently completed study, 77 % of participants were in full remission at post-treatment and at one-year follow-up. In other words, the treatment not only helps most GAD clients get better, it also helps them stay better.